(i) Given (7/8), (64/16), (39/-12), (5/-4), (140/28)

The LCM of 8, 16, 12, 4 and 28 is 336

Multiplying the numerators and denominators to get the denominator equal to the LCM i.e. 336

Consider (7/8)

Multiply both numerator and denominator by 42, then we get

(7/8) × (42/42) = (294/336) ….. (1)

Consider (64/16)

Multiply both numerator and denominator by 21, then we get

(64/16) × (21/21) = (1344/336) ….. (2)

Consider (39/-12)

Multiply both numerator and denominator by 28, then we get

(39/-12) × (28/28) = (-1008/336) ….. (3)

Consider (5/-4)

Multiply both numerator and denominator by 84, then we get

(5/-4) × (84/84) = (-420/336) ….. (4)

In the above equation, denominators are same

Now on comparing the descending order is:

(140/28) > (64/16) > (7/8) > (5/-4) > (36/-12)

(ii) Given (-3/10), (17/-30), (7/-15), (-11/20)

The LCM of 10, 30, 15 and 20 is 60

Multiplying the numerators and denominators to get the denominator equal to the LCM i.e. 60

Consider (-3/10)

Multiply both numerator and denominator by 6, then we get

(-3/10) × (6/6) = (-18/60) ….. (1)

Consider (17/-30)

Multiply both numerator and denominator by 2, then we get

(17/-30) × (2/2) = (34/-60) ….. (2)

Consider (7/-15)

Multiply both numerator and denominator by 4, then we get

(7/-15) × (4/4) = (28/-60) ….. (3)

In the above equation, denominators are same

Now on comparing the descending order is:

(-3/10) > (7/-15) > (-11/20) > (17/20)